我不知道什麽原理，但看到用高了並不好。

According to USA Today, some luxury cars from Ford and GM, such as the 2009 Lincoln MKS and the Cadillac STS, have been specifically manufactured to use regular unleaded fuel.

If your car happens to be one of these examples, not only will you get no advantage from using premium fuel, but it may actually be harmful to the car's engine in the long run.